From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Thu Feb 06 2003 - 10:39:42 MST
On Thu, 6 Feb 2003, Russell Blackford wrote:
> Okay, imagine a fairly full-on nuclear exchange causes a dark nuclear winter
> of several months' duration. Imagine further that the global climate
> thereafter tips over into something like ice-age temperatures. [snip]
>
> IF it happened like this, what would the major tropical/equatorial forests
> of places like Brazil look like after, say, 15-30 years? Presumably they
> would die but a lot of the big trees would remain standing. What sort of new
> vegetation could we expect to grow in what waa left of these jungles?
It really depends on how dark it gets for how long. The Sagan lengthy
nuclear winter hypothesis has been fairly disproven I believe.
First, many of the below canopy plants stand a good chance of surviving.
They are adapted to very low light conditions -- unless the "winter"
created *really* extended, totally dark conditions, some sunlight would
still make it through the clouds/fog. Then you have to consider rain
forest plants -- these spend much of their time under a lack of direct
sun (in Seattle this is 7-8 months a year even not being in a rain
forest). Finally, if the temperatures drop there are many plants
from tundra and high altitude environments that will just migrate
southward and to lower altitudes respectively.
It might also depend what time of the year the nuclear exchange
took place. Many plants, particularly in temperate zones store
a lot of their resources in their roots during the winter.
Provided some sunlight returns by the spring they are likely
to recover fairly well. Equatorial forests do not do this
but the under-canopy growth should stand a fighting chance.
A better question might be how the "endarkenment" might
impact rainfall. Less sunlight means less evaporation means
less rain (even though the small atmospheric particles might
be better at seeding increased rainfall). The plants are
likely to suffer more from a lack of water (which drives
photosynthesis) than a lack of sunlight.
Robert
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